Fig. 1

Genotype and phenotype of index patients with IMNEPD. a Scheme of PTRH2 mRNA and protein indicating the site of mutations in exon 2, the only coding exon of PTRH2. The mutation c.254A > C was previously reported [2]. b Electopherograms depicting the PTRH2 nonsense mutation of the original IMNEPD family (left) and the missense mutation of the further identified IMNEPD families (right). c Pedigrees of consanguineous families with IMNEPD (left: family 1 previously reported in Hu et al. 2014 [1], middle: family 2, right: family 3). d Mild facial dysmorphism of IMNEPD patients with phenotypic variability. Some patients show mild midface hypoplasia, a thin upper lip vermilion, and bilateral ptosis. e Cranial MRI of index patients (top: sagittal, below: coronal plane). Both patients with a PTRH2 missense mutation (family I, II.2 and II.4) show marked cerebellar atrophy while only one patient with a missense mutation (patient II.1, family 3) was diagnosed with cerebellar atrophy (white arrows)